We thank Komorowski and Juturu (1) for their interest in our study, and we agree that it is possible that higher doses of chromium may show some effects. The subjects in this study received 100 μg of elemental chromium daily, administered as 800 μg of chromium picolinate, for 3 months. The small increase in serum chromium in the active group is probably appropriate for this dose. It is worth noting that significant uncertainty remains regarding how best to measure whole-body chromium status, as there are no well-defined outcomes to allow determination of a therapeutic range. This unfortunately includes assaying of serum.
The Australian Therapeutic Goods Administration daily dose recommendation was adopted in 2004 and is based on concerns about the safety of higher doses as raised by the Complementary Medicines Evaluation Committee (2), including two reports of renal failure (3,4). Our study commenced before 2003 and was scientifically reviewed by our local ethics committee.
We do not agree that the results of the study conflict with the literature. Studies of chromium supplementation in nondiabetic subjects and people with normal glucose tolerance, insulin resistance, and/or impaired glucose tolerance (IGT) have not produced any consistent benefits, as reviewed by Cefalu et al. (5), Yeh et al. (6), Althuis et al. (7), and Gunton et al. (8). In contrast, some studies in subjects with diabetes have shown significant benefits (5,8), and further studies in this group will be of great interest.
Our study was conducted in people diagnosed with impaired glucose tolerance according to the American Diabetes Association criteria. Efficacy was also evaluated using area under the curve during glucose tolerance testing, but this was also nonsignificant (data not shown). We feel that at this dose, chromium picolinate supplementation in subjects with impaired glucose tolerance is ineffective.
We note that Komorowski and Juturu are affiliated with Nutrition 21, Inc., which markets chromium picolinate.